Handle portion of hand-held electric tool

ABSTRACT

Three battery cells can be arranged such that one battery cell is situated on the front side of a handle portion and that the remaining two battery cells are situated on the rear side thereof while being arranged laterally side by side. Also, a handle portion can be generally of a triangular cross-sectional configuration whose apex portion is situated on the front side of the handle portion and whose base portion is situated on the rear side thereof; and the handle portion is grasped by bringing fingertips into contact with the apex portion ( 11   a ) on the front side.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.12/676,781 filed Apr. 7, 2010, which is a U.S. National StageApplication of International Patent Application No. PCT/JP2008/065742filed Sep. 2, 2008, which claims the benefit of priority to JapanesePatent Application No. 2007-327217 filed Dec. 19, 2007 and to JapanesePatent Application No. 2007-239121 filed Sep. 14, 2007, the contents ofwhich are incorporated herein by reference in their entirety.

TECHNICAL FIELD

This invention relates to a handle portion of a hand-held electric toolthat is held with a hand during use.

BACKGROUND ART

As an electric tool, such as a battery type drilling tool, which isequipped with a handle portion provided so as to protrude sidewise froma side portion of a generally columnar tool main body, there has beenprovided a tool whose handle portion is loaded with a battery pack asthe power source.

Regarding such a hand-held, battery type electric tool, the followingpatent document, for example, DE 10 2005 036 449 A1, discloses atechnique related to a lock mechanism for fixing a battery pack havingthree columnar battery cells in position in a battery accommodationspace in a handle portion.

SUMMARY OF THE INVENTION

However, according to the technique disclosed in the above-mentionedpatent document, there is also a battery pack in which the three batterycells are arranged not laterally side by side but in a triangularfashion, with the three battery cells being situated at the apexes of atriangle, and this battery pack is loaded such that the front surfaceside of the handle portion constitutes a flat surface. Thus, thefingertips of the hand holding the handle portion are held in contactwith the flat surface, whereas the palm of the hand is held in contactwith an apex of the triangle, resulting in a handle configuration whichis rather hard to grasp for the user grasping the handle portion.

In the case, in particular, of a small hand-held electric tool, theoperation is usually performed with the electric tool supported with onehand grasping the handle portion, so that the workability may greatlydepend on the grasping feel (how it is felt when grasped, or ease ofgrasping). In the case, for example, of a drilling tool, since thehandle portion is hard to grasp, it is rather hard for the user to applyforce (pressing force) through his hand when pressing the forward endtool against the workpiece, which impairs the workability.

Therefore, there is a need in the art for enhancing the operability(usability) of an electric tool by improving the grasping feel of ahandle portion.

In one aspect of the present invention when a cross-sectionalconfiguration of the handle portion is assumed to be a triangle, an apexportion of the triangle is situated on a fingertip side of a graspinghand, and a base of the triangle is situated on a palm side. That is,the apex portion of the triangle is situated on the front surface sidethat is the forward end side of the tool main body, and the base of thetriangle is situated on the rear surface side. Thus, when the usergrasps this handle portion, the fingertips are brought into contact withthe apex portion side, and the palm is brought into contact with thebase side, so that it is possible to improve the grasping feel, and atthe same time, it is easier for the requisite force to be applied when atool bit attached to the forward end of the tool main body is to bepressed against a workpiece, whereby it is possible to improve theoperability or usability of the electric tool.

Here, regarding the cross-sectional configuration of the handle portion,the term “triangle” is not restricted to a mathematically exact trianglebut may include one having sides curved to generally form a circularconfiguration but having in its periphery three portions that may beregarded as apex portions (corner portions of an arcuate sectionalconfiguration) due to their increased curvature (reciprocal of theradius of curvature) and allows it to be regarded generally as atriangle. If anything, the handle portion of a hand-held toolcorresponds to the latter type of triangle. As a result, when the usergrasps the handle portion, the fingertips are brought into contact witha portion corresponding to an apex portion with large curvature, and thepalm is brought into contact with a portion corresponding to the basewith smaller curvature. In this case, the user finds the handle portioneasier to grasp, with the grasping feel thereof being thus enhanced.

Further, since the palm is held in contact with a portion correspondingto the base of the triangle, it is easier to apply force when pressingthe electric tool against the work, whereby it is possible to enhancethe operability or usability of the electric tool.

In another aspect of the present invention, the handle portion can beloaded with a battery pack having three battery cells and has atriangular cross-sectional configuration in correspondence with atriangular arrangement, in which one battery cell of the three batterycells is arranged on a front side and the other two battery cells arearranged on a rear side of the one battery cell while being arrangedlaterally side by side. That is, in the case of a battery pack in whichthree battery cells are arranged not laterally side by side but in atriangular fashion in a pyramid-like form, the battery pack generallyexhibits a triangular cross-sectional configuration. An apex of thistriangular cross-sectional configuration is situated on the frontsurface side of the handle portion, and the base thereof is situated onthe rear surface side; in correspondence with this, it is possible toarrange a portion with large curvature of the cross-sectionalconfiguration of the handle portion (a portion corresponding to an apexof the triangle) on the front surface side, and to situate a portionwith small curvature (a portion corresponding to the base of thetriangle) on the rear surface side (the user side).

Since a portion of large curvature is situated on the front surface sideof the handle portion, and the fingertips are held in contact with thisportion, the user feels the handle portion easier to grasp, so that itis possible to enhance the grasping feel thereof.

Further, on the front side as seen from the user, there is situated asurface of smaller curvature (a curved surface more akin to a flatsurface), and the palm is held in contact with this portion akin to aflat surface, so that it is easier for the user to apply a pressingforce to the electric tool to press it against the work, which helps toimprove the operability or usability of the electric tool.

In another aspect of the present invention, the handle portion has threebattery cells disposed therein and has a triangular cross-sectionalconfiguration in correspondence with a triangular arrangement, in whichone battery cell of the three battery cells is arranged on a front sideand the other two battery cells are arranged on a rear side of the onebattery cell while being arranged laterally side by side. The apexportion of the triangle is situated on a front side and the base of thetriangle is situated on a rear side with respect to a tool main body.With this arrangement, also in the battery cell containing type, it ispossible to obtain the same effect as that of the battery pack typedescribed above.

In another aspect of the present invention, the battery pack has threebattery cells, one battery cell of the three battery cells is situatedon a front side of a tool main body, and the remaining two battery cellsare situated on a rear side of the tool main body while being arrangedlaterally side by side. Thus, conversely to the prior art, the threebattery cells are arranged in a triangular configuration (in a pyramidform) such that the apex portion is situated on the front side of thehandle portion, with the base being situated on the rear side, so thatthe cross-sectional configuration of the handle portion can be of agenerally triangular configuration which is peaked on the front side (acurved surface of large curvature) and which is curved more gently onthe rear side (a curved surface of small curvature). As a result, thehandle portion to he loaded with the battery cells can be formed in across-sectional configuration that is easy to grasp, thereby improvingthe operability and usability of the electric tool.

In other aspect of the present invention, a battery pack is configuredsuch that the battery pack has a pair of right and left fixation clawportions to be engaged with the handle portion, the fixation clawportions are equipped with finger-rest portions inclined in suchdirections that they approach to each other toward the apex portion, andthe engagement with the handle portion is canceled by pressing thefinger-rest portions with fingertips in such directions that theyapproach to each other. Further the battery pack is configured such thatthe finger-rest portions are provided with anti-slip portions forpreventing the fingertips from slipping toward the apex portion.Therefore, the fixation claw portion releasing operation can beperformed reliably and easily. In the case in which the right and leftfinger rest portions are, inclined in such directions that they approachto each other toward the apex portion side, when both finger-restportions are pushed by fingertips, the fingertips are likely to sliptoward the apex portion side, thus making it rather hard to perform thereleasing operation. In this respect, anti-slip portions are provided onthe finger rest portions so that the fingertips may not slip toward theapex portion side, whereby it is possible to reliably perform pushingoperation on both finger-rest portions and, by extension, it is possibleto quickly perform the operation of releasing the right and leftfixation claw portions, thus facilitating the detachment of the batterypack.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 A general side view of an electric tool equipped with a handleportion according to the embodiment shown. The drawing shows the generalinner structure of the rear portion side of the tool main body and thehandle portion.

FIG. 2 A sectional view taken along the arrow line (2)-(2) of FIG. 1.The drawing illustrates a state in which the user is grasping the handleportion with the right hand.

FIG. 3 A cross-sectional view of a battery pack equipped with fixationclaw portions having anti-slip portions.

FIG. 4 A general perspective view of the battery pack equipped withfixation claw portions having anti-slip portions. The drawing shows thebattery pack as detached from the handle housing.

DETAILED DESCRIPTION OF THE INVENTION

Next, an embodiment of the present invention will be described withreference to FIGS. 1 and 2. FIG. 1 is a general view of a hand-held typeelectric tool 1 equipped with a handle portion 10 according to theembodiment. In this embodiment, as an example of the hand-held typeelectric tool 1, there is shown a relatively small drilling tool. In thefollowing description, regarding the directions of the members,portions, etc., the direction in which drilling is performed will bereferred to as the front side or forward end side, and the directionopposite thereto will he referred to as the rear side.

The electric tool 1 is equipped with a tool main body 2 of a generallycolumnar configuration. The handle portion 10 is provided so as toprotrude from a side portion of the tool main body 2. A main bodyhousing 6 of the tool main body 2 and a handle housing 11 of the handleportion 10 are formed integrally with each other.

At the forward end (the right-hand end in FIG. 1) of the tool main body2, there is provided a chuck 2 for attaching a tool bit T. By pressingthe tool bit T against a workpiece W, the workpiece W is drilled. Thetool main body 2 has an electric motor 4 disposed therein. Using theelectric motor 4 as the drive source, the tool bit T rotates about itsaxis. The electric motor 4 is started by pulling a trigger type switchlever 5 arranged on the front side of the base portion of the handleportion 10 with a finger.

Regarding the tool main body 2, no particular modification is requiredin carrying out the present invention, so a detailed description thereofwill be omitted.

The handle portion 10 has a thickness and a sectional configurationsuited to be grasped by the user with one hand. A rechargeable typebattery pack 20 is attached to the leading end portion (the lower endportion in FIG. 1) of the handle portion 10 (handle housing 11). Theelectric tool 1 shown is operated by using the battery pack 20 as thepower source. That is, the electric motor 4 is started by using thebattery pack 20 as the power source.

As shown in FIG. 2, the battery pack 20 has a battery case 24 containingthree battery cells 21 through 23. At the lower end portion of thebattery case 24, there is provided a cover portion 24 a. When thebattery pack 20 is attached to the handle portion 10, the cover portion24 a serves as a cover covering the interior (battery accommodationspace) of the handle housing 11. A pair of right and left fixation clawportions 24 b, 24 b are provided on the right-hand and left-hand sideportions of the cover portion 24 a. The right and left fixation clawportions 24 b, 24 b are engaged with the handle housing 11, whereby thebattery pack 20 is maintained in the attached state. When both fixationclaw portions 24 b, 24 b are pushed with fingertips to cancel theengagement state with respect to the battery housing 11, it is possibleto remove the battery pack 20 from within the handle case 11, and torecharge the removed battery pack 20 or replace it with a new one.

The three battery cells 21 through 23 each have a columnar configurationand are arranged not laterally side by side but in a triangular fashion(in a pyramid form) with the battery cells being situated at positionscorresponding to the apexes of a triangle. In the following, thisarrangement will also be referred to as the triangular arrangement. Asshown in the drawing, in this example, the battery cells 21 through 23are arranged in a triangular fashion in such a relationship that thecenter axes 21 a through 23 a of the battery cells 21 through 23 aresituated at the respective apexes of an equilateral triangle.

Due to the above-described triangular arrangement of the three batterycells 21 through 23, the battery case 24 also has a generally triangularcross-sectional configuration. However, the three corner portions (whichare situated at the positions corresponding to the apexes of thetriangle) of the battery case 24 are formed as arcuate surfaces curvedwith curvatures in conformity with the peripheral surfaces of thebattery cells 21 through 23. In the description of this specificationand the claims, “triangular” refers to also this configuration. In thistriangular arrangement, one battery cell 23 is arranged on the frontside, and the remaining two battery cells 21, 22 are arranged laterallyside by side on the rear side thereof, with the battery cells being incontact with each other.

The handle housing 11 is also of a generally triangular cross-sectionalconfiguration in correspondence with the battery case 24, in which thethree battery cells 21 through 23 are arranged in a triangular fashionand which, consequently, has a triangular cross-sectional configuration,and eventually, in correspondence with the battery pack 20. The batterypack 20 is loaded in the handle housing 11, with its portioncorresponding to the apex of the triangle being situated on the frontside, and the portion corresponding to the base of the triangle beingsituated on the rear side. Thus, the handle housing 11 has a generallytriangular cross-sectional configuration, with an apex portion 11 a of alarge curvature being situated on the front side, and a base portion 11b of a smaller curvature being situated on the rear side.

Therefore, when the user grasps the handle portion 10, the fingertipsare brought into contact with the apex portion 11 a on the front side,and the palm is brought into contact with the base portion 11 b on therear side, so that, as compared with that of the prior-art construction,which is of a reverse arrangement, the handle portion is easier tograsp.

The handle portion 10 of this embodiment, constructed as describedabove, has a generally triangular cross-sectional configuration, withthe apex portion 11 a nearer to an acute angle (of a larger curvature)being situated on the front side, and the base portion 11 b nearer to aflat surface (of a smaller curvature) being situated on the rear side.Thus, as shown in FIG. 2, the user can grasp the handle portion 10 withone hand H, with the fingertips Hf being hooked on the apex portion 11a, and the palm Hp being pressed against the base portion 11 b, so thatit is possible to grasp the handle portion 10, resulting in a moresatisfactory grasping feel than in the prior art.

Further, since it is possible to grasp the handle portion, with the palmHp being pressed against the base portion 11 b on the rear side, whichis nearer to a flat surface, it is easier to apply a pressing force P tothe handle portion 10, which is necessary to be applied to the electrictool 1 for a drilling operation, and therefore, it is possible toimprove the operability and usability of the electric tool 1 in thisrespect.

The above-described embodiment can be carried out in various modifiedforms. As described above, the battery pack 20 can be removed fromwithin the handle case 11 by canceling the engagement state with respectto the battery housing 11 by pushing the right and left fixation clawportions 24 b, 24 b with fingertips. As shown in FIG. 2, the finger-restportions of the right and left fixation claw portions 24 b, 24 b arearranged to extend along two side surfaces of the triangular sectionalconfiguration, with the result that they are arranged so as to beinclined in such directions that they approach to each other toward theapex portion 11 a of the battery housing 11. For this reason, in somecases, when the finger-rest portions of the right and left fixation clawportions 24 b, 24 b are pressed so as to be held from both sides by, forexample, the thumb and the index finger, the fingertips may slip on thefinger-rest portions toward the apex portion 11 a to make the pushingoperation difficult since the finger-rest portions are not orthogonal tothe pressing directions but are inclined with respect thereto atrelatively large angles.

FIGS. 3 and 4 show a battery pack 30, in which, in order to solve theabove-mentioned problem, anti-slip portions 31 b, 32 b are respectivelyprovided on finger-rest portions 31 a, 32 a of right and left fixationclaw portions 31, 32. In the example shown, the anti-slip portions 31 b,32 b are provided on the front side of the finger-rest portions 31 a, 32a. At each of the right and left finger-rest portions 31 a, 32 a, threelateral ribs are arranged vertically. A range of substantially the fronthalf of each rib protrudes sidewise, and the leading end surface thereof(the surface with which a fingertip contacts) is formed in a state ofbeing bent into a V-shape, whereby the anti-slip portions 31 b, 32 b areprovided.

The anti-slip portions 31 b, 32 b are arranged so as to be substantiallyparallel to each other, and are provided so as to be generallyorthogonal to the pressing directions of the fingers.

Due to the anti-slip portions 31 b, 32 b, slipping of the fingertipstoward the apex portion 11 a is prevented, and it is possible toreliably press both finger-rest portions 31 a, 32 a, whereby it ispossible to improve the usability of the battery pack 30. Around theright and left anti-slip portions 31 b, 32 b, there are provided guardportions 31 c, 32 c protruding sidewise at substantially the sameheight. Due to the guard portions 31 c, 32 c, it is possible to preventthe finger-rest portions 31 a, 32 a (or the anti-slip portions 31 b, 32b) from being inadvertently pressed.

Also with the battery pack 30 equipped with anti-slip portions, threebattery cells similar to those mentioned above are arranged in atriangular fashion, enabling the handle portion 10 to be easily grasped.

The embodiments described above allow further modifications. Forexample, while the battery pack 20 described above has three batterycells 21 through 23, application to the case of a battery pack havingfour or more battery cells is possible in the same manner. In the caseof four battery cells, it is possible to form the handle portion in agenerally triangular cross-sectional configuration by a pyramid-likearrangement in which one battery cell is situated on the front side, andin which three battery cells are arranged laterally side by side on therear side. In the case of five battery cells, it is possible to realizea battery pack in which the battery cells are arranged in a generallypyramid-like configuration, by positioning one battery cell in a frontrow, two battery cells in a middle row, and two battery cells in a rearrow.

In the case of six battery cells, it is possible to realize a batterypack in which the battery cells are arranged in a pyramid-likeconfiguration, by arranging one battery cell in the front row, and byarranging two battery cells and three battery cells laterally side byside in the intermediate row and the rear row, respectively. Further, inthe case of a battery pack accommodating six battery cells, it ispossible to attain the same effect by accommodating the battery cells intwo, upper and lower stages in the longitudinal direction of the handle,with three battery cells being arranged in a triangular fashion at eachstage.

By arranging a plurality of battery cells in a pyramid-like (triangular)fashion in these ways, it is possible to realize a handle portion of agenerally triangular cross-sectional configuration; and it is possibleto attain the same effect by situating the apex portion on the frontside and the base portion on the rear side. Thus, applications arepossible not only to the battery pack type tool in which a battery packaccommodating three or more battery cells is loaded in the handleportion, but also to a cell containing type tool in which three or morebattery cells are directly contained in the handle portion without theintermediation of a battery pack. In short, it is possible to realize ahandle portion that can be more easily grasped by setting thecross-sectional configuration of the handle portion to be generallytriangular, with the apex portion thereof being on the front side, andthe base portion thereof being on the rear side, regardless of thecross-sectional configuration of the battery pack or the arrangementconfiguration of the battery cells. Thus, the present invention is alsoapplicable to an electric tool of a type in which no battery pack isloaded in the handle portion, for example, an electric tool using an ACpower source as the power source.

Further, while a drilling tool (a so-called electric drill) has beenillustrated as an example of the electric tool, applications to electrictools for performing the other operations, such as a screw fasteningoperation, are possible.

The invention claimed is:
 1. A hand-held type electric tool comprising:a tool main body extending in a forward and rearward direction; a handlehousing extending downward from the tool main body; a chuck disposed ona front side of the tool main body; a switch lever disposed on thehandle housing; and a rechargeable type battery pack; wherein: thehandle housing is configured to receive at least a part of therechargeable type battery pack: the rechargeable type battery packincludes three battery cells and a battery case; the three battery cellsinclude one battery cell and two battery cells arranged on a rear sideof the one battery cell; the battery case includes a cover portion whichis attached to a lower end portion of the handle housing and a fixationclaw portion, wherein the fixation claw portion can be used to attachthe rechargeable type battery pack to the handle housing and thefixation claw portion is arranged so as to be capable of being graspedby the user; the handle housing has a substantially triangular crosssectional configuration such that the handle housing has i) an apexportion disposed on a front side of the handle housing and ii) a baseportion disposed on a rear side of the handle housing, the lower endportion of the handle housing has an outer shape that substantiallyconforms to an outer shape of the cover portion of the battery case, inthe substantially triangular cross sectional configuration, a maximumdimension of the handle housing in a direction perpendicular to theforward and rearward direction is located on a front side of a maximumdimension of the battery case where the two battery cells are disposed,and the fixation claw portion is located between the one battery celland one of the two battery cells in the forward and rearward direction.2. The hand-held type electric tool according to claim 1, wherein thefixation claw portion includes a right fixation claw disposed on a rightside of the rechargeable type battery pack, and a left fixation clawdisposed on a left side of the rechargeable type battery pack.
 3. Thehand-held type electric tool according to claim 2, further comprising anelectric motor disposed within the tool main body and located on anupper side of the rechargeable type battery pack.
 4. The hand-held typeelectric tool according to claim 2, wherein the battery case furtherincludes a right finger-rest portion disposed on a lower side of theright fixation claw, and a left finger-rest portion disposed on a lowerside of the left fixation claw.
 5. The hand-held type electric toolaccording to claim 4, wherein the right finger-rest portion includesright ribs, and the left finger-rest portion includes left ribs.
 6. Thehand-held type electric tool according to claim 2, wherein the coverportion is disposed at a lower portion of the battery case and has anupper end and a lower end, and wherein the right fixation claw and theleft fixation claw are both disposed above the upper end of the coverportion.
 7. The hand-held type electric tool according to claim 6,wherein a right finger-rest portion and a left finger-rest portion arepositioned at substantially the same level as the upper end of the coverportion.
 8. The hand-held type electric tool according to claim 6,wherein the right fixation claw portion is disposed on the right side ofthe one battery cell, and the left fixation claw is disposed on the leftside of the one battery cell.
 9. The hand-held type electric toolaccording to claim 1, wherein the three battery cells are disposed on alower side of the switch lever.
 10. A hand-held type electric toolcomprising: a tool main body extending in a forward and rearwarddirection; a handle housing extending downward from the tool main body;a chuck disposed on a front side of the tool main body; a switch leverdisposed on the handle housing; and a rechargeable type battery pack;wherein: the handle housing is configured to receive at least a part ofthe rechargeable type battery pack: the rechargeable type battery packincludes three battery cells and a battery case, the battery caseincluding a fixation claw portion, at least part of the battery casehaving a substantially triangular cross sectional configuration andbeing disposed within the handle housing; the three battery cellsinclude one battery cell and two battery cells arranged on a rear sideof the one battery cell, the handle housing has a substantiallytriangular cross sectional configuration corresponding to the triangularcross sectional configuration of the at least part of the battery case,the handle housing including i) an apex portion having a first curvatureand being disposed on a front side of the handle housing and ii) a baseportion having a second curvature which is smaller than the firstcurvature and being disposed on a rear side of the handle housing, inthe substantially triangular cross sectional configuration, a maximumdimension of the handle housing in a direction perpendicular to theforward and rearward direction is located on a front side of a maximumdimension of the battery case where the two battery cells are disposed,and the fixation claw portion is located between the one battery celland one of the two battery cells in the forward and rearward direction.11. The hand-held type electric tool according to claim 10, wherein thebattery case includes a cover portion and the fixation claw portion,wherein the fixation claw portion can be used to attach the rechargeabletype battery pack to the handle housing.
 12. The hand-held type electrictool according to claim 11, wherein the fixation claw portion includes aright fixation claw disposed on a right side of the rechargeable typebattery pack, and a left fixation claw disposed on a left side of therechargeable type battery pack.
 13. The hand-held type electric toolaccording to claim 12, further comprising an electric motor disposedwithin the tool main body and located on an upper side of therechargeable type battery pack.
 14. The hand-held type electric toolaccording to claim 13, wherein the handle housing includes an apexportion situated on a front side of the handle housing and a baseportion situated on a rear side of the handle housing.
 15. The hand-heldtype electric tool according to claim 12, wherein the battery casefurther includes a right finger-rest portion disposed on a lower side ofthe right fixation claw, and a left finger-rest portion disposed on alower side of the left fixation claw.
 16. The hand-held type electrictool according to claim 15, wherein the right finger-rest portionincludes right ribs, and the left finger-rest portion includes leftribs.
 17. The hand-held type electric tool according to claim 12,wherein the cover portion is disposed at a lower portion of the batterycase and has an upper end and a lower end, and wherein the rightfixation claw and the left fixation claw are both disposed above theupper end of the cover portion.
 18. The hand-held type electric toolaccording to claim 17, wherein a right finger-rest portion and a leftfinger-rest portion are positioned at substantially the same level asthe upper end of the cover portion.
 19. The hand-held type electric toolaccording to claim 17, wherein the right fixation claw portion isdisposed on the right side of the one battery cell, and the leftfixation claw is disposed on the left side of the one battery cell. 20.The hand-held type electric tool according to claim 10, wherein thethree battery cells are disposed on a lower side of the switch lever.